Just stop thinking like that. I'm telling you, you're just digging deeper for no reason. Take a deep slow breath when you are starting to panic.

One thing I've noticed about me is when I'm with friends them being there seems to deaden my not wanting to be around people... Example: Last Halloween I was with my friends and then we went to his sister's house for a Halloween party. We got there before everyone else, so as people slowly starting showing up I didn't much mind. Though if it was just me going and I got there after all the guests arrived, I'd probably get really uncomfortable and sit in a far corner of the least populated room or leave.

Seems like a good idea to get there early so you can meet the people.

I've started picking up interests in some things. It keeps my mind off things. One being that I like this girl and I think she likes me too, but not too sure yet. I've decided to go back to programming, whenever I feel nervous I start thinking of what things I could do to improve my code and such. I still get ridiculously nervous when people get in my "bubble".

Here is the greatest advice in attempting to pursue a girl. When you're talking or interacting with her, don't think about liking her. Just talk to her like she's a normal person and find common interests. If you get signals that she is into you, then take it slowly and advance forward steadily. If she isn't into you or doesn't want to talk to you, don't continue and forget her. There are plenty of fishes in the sea.

you might have some sort of anxiety disorder, the doctor could prescribe you something like Valium, but i'd try the other suggestions first, they're probably right.